The major aim of this grant is to assess the effects of dietary alterations on changes in the metabolism and turnover of elastin. Most recently some evidence has been provided that proforms of the known soluble precursor of fibrous elastin exist. Soluble elastin or tropoelastin appears to be synthesized from protein subunits in excess of 100,000 daltons in size. Also, it has been observed that dietary cholesterol influences the rates at which tropoelastin is synthesized. This effect does not appear to be related to changes in the rates of degradation of tropoelastin, which is not altered by dietary cholesterol. Evidence has also been obtained that tropoelastin is the most immediate precursor to fibrous elastin. These relationships and characterization of the proteins involved are currently being investigated. Furthermore, it has been observed that agents which act as vasoconstrictors often appear to effect decreased incorporation of radioactively labeled amino acids into elastin, where as vasodilators appear to have little apparent effect on incorporation. This process appears not to be related to cyclic-AMP mediated effects on amino acid uptake or protein synthesis by chick aorta.